Mercury-vapor apparatus.



P. H. THOMAS.

MERCURY VAPOR APPARATUS.

APPLICATION FILED OCT-19. 1904.

Patented Nov. 7 1916.

2 SHEETSSHEET 1 P. H. THOMAS.

MERCURY VAPOR APPARATUS. APPLICATION FILED OCT- I9. 1904.

1 ,203,8 1 2 Patented Nov. 7, 1916.

2 SHEETSSHEET 2- UNITED STATES PATENT omen.

PERCY H. THOMAS, OF EAST ORANGE, NEW JERSEY, A SSIGNO R, BY MESNE ASSIGN MENTS, TO COOPER HEWITT.ELECTRIC COMPANY, OF HOBOKEN, NEW JERSEY, A

CORPORATION OF NEW JERSEY.

MERCURY-VAPOR APPARATUS.

Specification of Letters Patent.

Original application filed July 19 1904, Serial No. 217,170. Divided and this application filed October 19, 1904. Serial No. 229,048.

To all whom it may concern:

Be it known that I, PERCY H. THoMAs, a' citizen of the UnitedStates, and resident of East Orange, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Mercury-Vapor Apparatus, of which the following is a specification.

The starting of mercury vapor apparatus by means of a filament, say of carbon, connecting the positive and negative electrodes or adapted to be connected therewith is described by me in an application filed April 25, 1904 in the United States Patent Oflice, Serial Number 204,712, and patented June 29th, 1915, No. 1,144,396. In this form of vapor apparatus the starting takes place through breaking a contact either originally existing or temporarily formed between the free end of the filament and the electrode which happens to be most remote from the supporting point of. the said filament, whereupon a flow of current is established between the said electrode and the free end of the filament; this flow of current creeping forward to the supporting end of the filament and thus to the other electrode.

It is found in operating vapor lamps and converters that it is possible to maintain a flow of current between electrodes through a portion of the vapor much more easily when current has once been established than before its establishment. This may result from the action of residual gas found in the container which has to be pierced by the electric particles forming the current before the electrodes can be bridged. Once a current of definite value is established, it has a definite voltage which drops continuj ously from one electrode to the other. Suppose this vapor column carrying current to be in parallel-within the chamber with a conducting filament; the current has the choice of two paths, one through the filament and one through the vapor. It will ordinarily divide between the two, enough the filament to the positive electrode. The

current flowing through the filament to maintain the voltage drop the same as that through the vapor.

If we assume that, under the described;

conditions, the current decreases in the divided circuit, the voltage of the vapor will increase, causing a greater proportionof fully started into operation;

At a certain point in the general decrease of -current, the voltage of the vapor will rise very rapidly until all the current passes through the filament. On the other hand, if

we increase the current through the divided circuit, a greater proportion will fiow through the vapor causing a lowering of its voltage and withdrawing current from the filament. The fact that the voltage of the rent be established between the end'of the filament and the negative electrode of the apparatus, there may be a point on the filament near its end between which and the end of the filament the voltage drop is greater than the normal drop through the vapor when the apparatus has been care- Under these conditions, the point at which the current enters the filament from the vapor will be determined by the relative voltages as above described, but this point will creep along the filament toward the positive electrode,

since by so doing the total resistance of the circuit is lessened. This movement of the point of entrance will finally extend to the positive electrode itself, provided the filament is of proper resistance taken in connection with the value of the current employed and the vapor conditions, although the current might not .,be able to pass at once from the positive electrode to the negative electrode through the vapor without the presence of the filament.

The filament 8 is a high resistance conductor. It is evident this quality of. high resistance, which means resistance high relatively to the vapor path as explained above, causes the arc to extend onward along higher the resistance'of the filament with a given current flowing, the greater the voltagetending to be impressed upon the vapor path shunting the filament and thus the stronger the tendency for. current to flow therein. :Conversely, if the resistance of the filament is less than a certain definite value,

' unit length more or less independent of the current flowing and is further emphasized somewhat by the moderate rise of potential per unit length consequent upon relatively small values of current. When the filament is in an extension of a cathode, however, these conclusions do not necessarily hold on account of the peculiar property of a cathode, namely, its negative electrode starting reluctance.

The present invention relates to an improvement of the previous invention, particular reference being had to the providing means whereby the several parts inclosed within the container of the vapor apparatus can readily be freed from occluded gases and afterward act efiiciently as elements of a vapor lamp or converter.

The drawings show two embodiments of the invention, Figure 1 illustrating a vapor electric lampadapted-to operate in a horizontal position; Fig. 2 showing a modified form of lamp adapted to be operated in a vertical position; Fig. 3 being an end view of the lamp illustrated in. Fig. 1; and Fig.

4 showinga modification of the circuit connections in a lamp similar to that illustrated in Fig. 1.

In the drawings, 1 is the container of a vapor electric lamp or other vapor apparatus, 2 is the positive electrode thereof, and 3 is the negative electrode. The electrode 3 may be of mercury, while theelectrode 2 in the present instanceis a ring of" conducting material, say iron, the said ring being connected by a high resistance Wire, 4, with the positive lead-wire, 5, of the device. The negative electrode 3 is connected by a leadwire, 6, with the external circuit.

The lead-wire 5 extends into a sleeve, 7 of glass formed inside the end of the container 1, and its inner end is intimately connected both with the high resistance wire 4 and also with a filament, 8, which may be of carbon and which extends through a considerable portion of the length of the container 1. The filament is supported at one or more points on its length by a hook or hooks, 9, sealed into projecting portions of the glass constituting the container. v

To the other end of the filament 8 is secured a piece, 10, of iron, the same being placed so that its end dips into the mercury of the electrode 3 when the lamp is not in operation. Abovethe said iron piece 10 is located a magent, 11, which may be connected, as shown, in a high resistance shunt to the two electrodes, or may be in series with the electrodes, as illustrated in Fig. 4.

If located as shown, the magnet will be wound with a'very fine wire so as to ofler a high resistance to the passage of currentthrough it. The filament 8 passes through the central opening in the ring 2 and extends into connection with the inner end of the lead-wire 5, as described.

The magnet 11 is formed with pole-pieces arranged on opposite sides of the container 1 and just outside the iron piece 10 on the end of the filament 8. When energized, the magnet tends to exercisea torsional effect upon the iron piece or armature 10, whereby it may be lifted out of contact with the mercury 3 and into or toward the position indicated in dotted lines in Fig. 3. A flow of current being thus established between the said electrode and the iron piece 10 this flow is transferred along the filament to the electrode 2 in a manner now well understood.

In Fig. 2 the construction is generally the same as that described except that the filament 8 in the completed lamp does not extend into contact with the electrode 3, but reaches close down to its upper surface, the starting being accomplished by slightly shaking or agitating the apparatus so as to make a: momentary contact between the electrode and the end of the filament. When the mercury settles oack a rupture of the circuit is made and the lamp starts into operation as before.

Referring again to Fig. 1, the construction therein embodied is found to be particularly well adapted to the purpose of a lamp or vapor apparatus of this class by reason of the fact that all the solid conducting parts inside the apparatus can readily be exhausted of their occluded gases. For example, the gas can be removed from the filament during the process of manufacture by heating the same through the passage of an electric current; that is to say, by depending upon its ohmic resistance to the passage of current to bring it to a sufiicient heat for occluded gases by creating a heavy pressure within the chamber and running current through the apparatus from the electrode 3 as a negative to the iron tip 10 as a positive. Moreover, the stem 4, which may, for example, be of some well known high resistance conducting material, will have its gases removed by reason of its becoming heated through its ohmic resistance. That is, the

same current which is utilized to remove the gases from the anode 2 will at the same time heat the stem 4 to sufficient temperature to remove its gases, which makes a simple and economical method of securing an extremely high. and permanent vacuum.

I have found that the current which is sufficient to heat the anode, 2, properly will heat the stem, 4, as well, provided this be made of any high resistance material adapted to this purpose and that if low resistance material be used, such for example as is used ordinarily for conductors, that no current which the anode will support can ordinarily heat the stem sufiiciently todrive off deleterious gases.

Referring to Fig. 2, the treatment of most of the elements for purposes of removing injurious gases may he the same as that described in connection with'Fig. 1. In this construction it is convenient to place in the lamp during the process of manufacture mercury enough to touch the end of the filament 8 and to distil out the excess mercury .by heat, thus assisting in carrying away the superfluous gases. The heat can be applied by the electric current or by external means.

In another application filed by me on the 19th day of July, 1904, Serial Number 217,170, of which this application is a division, claims are made upon the method described herein.

I claim as my invention:

1. In a vapor electric apparatus wherein a filament extends through practically the entire distance between the main electrodes, a positive electrode in the form of a thin plate or disk surrounding the said filament, and connected to the positive lead-Wire by a high resistance conductor.

2. In a vapor electric apparatus wherein a filament extends through practically the entire distance between the main electrodes, a positive electrode in the form of a thin plate or disk surrounding the said filament, the filament being connected to the positive lead-wire and the ring electrode being also connected to the said lead-wire by a high resistance conductor.

3. A vapor electric apparatus adapted to operate in a horizontal position, comprising a suitable container and a positive and a negative electrode therein, in combination with a filament extending from the positive leadwire into proximity to the negative electrode, and a tip on said filament composed of magnetic material, and a magnet in cir cuit of the apparatus adapted to separate the said tip from the negative electrode when the circuit of the apparatus is closed.

Signed at New York, in the county of New York and State of New York, this 15th day of October, A. 'D'. 1904;

PERCY H. THOMAS. 

